大花序桉心边材的径向和轴向的变异

【目的】探究大花序桉心材与边材在树龄、横截面去皮直径和树高,即径向和轴向的变异规律,明确大花序桉心材发育过程中心、边材量的变化趋势,继而为培育大径级大花序桉以及木材高效利用提供科学依据。【方法】以广西东门林场5年、17年、29年、35年生的大花序桉为研究对象,测定其东、西、南、北4个方向的横截面去皮直径、去皮半径、心材半径、边材宽度,并拟合心、边材量与树龄、横截面去皮直径、树高之间的回归方程,研究大花序桉心、边材量轴向和径向的变异规律。【结果】心材半径和心材面积随着树龄的增加而增大,而边材宽度仅在5～29年之间变化较大,边材面积随树龄的变化不明显。在不同树龄间边材面积差异不显著(P> 0.05),心材半径、心材面积和边材宽度均存在显著差异(P <0.05)。横截面心材量随着横截面去皮直径的增加而增加,但横截面边材量与横截面去皮直径相关性较弱。当横截面去皮直径约为4.66 cm时,大花序桉开始形成心材,之后树干横截面去皮直径每生长1 cm,心材半径就增加约0.52 cm。各树龄大花序桉心材半径、心材面积和边材面积都随着树高的增加而减小,在树木基部最大,接近树梢处明显减小,边材...

Variation on radial and axial of heartwood and sapwood in Eucalyptus cloeziana

[Objective]In order to clarify the changing trend of heartwood and sapwood amount during the development of Eucalyptus cloeziana heartwood,and to provide scientific basis for the cultivation of largediameter E.cloeziana and efficient use of wood,the variation of heartwood and sapwood,stem crosssectional peeling diameter and height of E.cloeziana at different-aged was investigated.[Method]5-,17-,29-and 35-year-old E.cloeziana were used to determine the stem cross-sectional peeling diameter,peeling radius,heartwood radius and sapwood width in four directions of east,west,south,north.Besides,the regression equation of heartwood and sapwood amount and tree age,stem cross-sectional peeling diameter,tree height was established to analyze the axial and radial variation patterns of heartwood and sapwood E.cloeziana.[Result]The heartwood radius and heartwood area increased with the tree age,while the width of sapwood varied greatly between 5 and 29 years,but the sapwood area didn,t change significantly with tree age.There was no significant difference in the area of sapwood between different tree ages(P>0.05),and there were differences in the radius of heartwood,the area of heartwood and the width of sapwood(P<0.05).The amount of stem cross-sectional heartwood increased with the increase of stem cross-sectional peeling diameter,but the amount of stem cross-sectional sapwood was weakly correlated with stem crosssectional peeling diameter.When the stem cross-sectional peeling diameter was about 4.66 cm,E.cloeziana began to form heartwood,and then the diameter of trunk stem cross section grew by 1 cm,the heartwood radius increased by about 0.52 cm.The heartwood radius,heartwood area and sapwood area of E.cloeziana of each tree age decreased with the increase of tree height,the largest at the base of the tree,and the sapwood width decreased when the tree height was 1.0-5.3 m.There was a certain fluctuation,which was relatively constant above the height of 5.3 m.[Conclusion]The amount of heartwood is significantly positively correlated with tree age and stem cross-sectional peeling diameter,and negatively correlated with tree height.The study suggests that the 35-year-old E.cloeziana still has great growth potential and can be further cultivated for the large-diameter E.cloeziana.